Electric furnace.



W. N. CRAFTS.l

ELECTRIC FURNACE.

APPLIOATION FILED 0013.15, 1912.

Patented Aug. 12, 1913.

n, M m? INVENTOR L16 'Mari E5.'

Erw@ 5' 62% @LM/r WALTER N. CRAFTS, or OBEBLIN, oHIo.

l ELECTRIC FURNACE.

Specification of Letters Patent.

. Patented Aug. 12,1913.V

Application filed October 15, 1912. Serial No. 725,351.

T0 all whom it may concern Be itv known that I, VVALTEaN. CRAFTS, acitizen of the 'United States, residing at Oberlin, in the county ofLorain and Stateof Ohio, have invented a. certain new and usefulImprovement in Electric Furnaces, of which the following is 'a full,clear, and exact description, reference being had to the accompanyingdrawings.

This invention relates to electric furnaces of the induction type,wherein there is a bath and a U-shapedpassageway for `moltenmetal-'communicating with the bath and constituting with a portion of itan annular secondary surrounding'the magneticcore of an induction'coil.In'such a furnace it is very desirable, to provide means enabling theseparation of the bath portion of the furnace from the supporting bodyIand the core and primary winding, as this allows the core, primary,Vand support to be used with another bath portion while the former isbeing repaired. 'It also provides for convenient repair of the primarywinding. YVith such separable furnace it is important to provide meanspreventing leaking from the legs of the U-shaped passageway at thejunction planes of the two portions of the body. Itis also desirable toso locate the primary winding that it will be preserved from destructionin case of leakage of hot metal when the furnace body wears or cracks.

The object of the present invention is to provide forefliciently,acco1nplishing`these results, and the invention may be mostconveniently summarized as co-mprising the means by which I attain suchobject.

The invention is hereinafter more fullydescribed` in connection with aconvenient embodiment of the invention, as shown in the drawings, andthe essential features of the invention are set out in the claims. v

In the-drawings, Figure 1 isa'side elevation of a tilting furnaceembodying my invention; Fig. 2 is a vertical central section of suchfurnace; Figs. 3 and 4 are horizontal sections of the furnace taken justabove the bath 'and through the core respectively; Fig. 5 is an enlargeddetail illustrating the means for preventing leakage at the junction ofthe upper and lower parts of the furnace body; Fig. 6 is a verticalsection of a furnace having a multiple U-passage, core and primary.`

Referringl to the parts by numerals, 10 represents the hearthl portionof the furnace body which is formed'of magnesite or similar materialland has a basin to carry the bath 11. y

12 isa suitablemetal casing around this portion, and 13 an arch or rooftherefor.

14 are the loading openings, close-d by doors 15, and 16 represents thepouring spout.

The to rest on a suitable under portion 3() and tilting iframe 20, shownin thg drawings. As there shown, the frame 1s pivotally mounted near itsfront end on brackets 22, while the rear' is supported by tilting rods24 hereinafter described. The frame work 20 carries the lowerfurnace-body 30, preferably made of magnesite and protected at the sidesand below by the meta-l shells 31 and 32. On this body 30 the hearthbody,

heretofore described, rests. The hearth body,

has a metal shell 17 extending under a portion thereof, but the artwhich comes over the magnesite 30 is o exposed magnesite, so that thetwoportions of the furnace may have a cemented, tight connection whenthey are in place.

To provide in the magnesite 10 and 30 one or more U- shaped passagewaysy33, or 33a in Fig. 6, adapted to contain molten metal form-ing one ormore annular secondaries with a portion of the molten metal in thebasin. The lower portion of the `Ushaped passageway `is carried in thebody 30, while the upper portion of the two legs of the U consists ofopenings 18 and 1.9.through'the bottom of the body 10, or 18 andthecommon portion 19a in Fig. 6. rFhese passageways in the reso positionedthat when the two parts of the furnace are together, as shown in Figs. 2and 6, there is acontinuous U-shaped pasagislway connecting with thematerial in the at The core of the induction coil, of which two areshown in Fig. 6, is designated 40. It is a laminated,preferably-rectangular, annular device suitably supported with one leg,as 41, between the arms of the U-shaped passageway. The opposite leg 42of the core may stand entirely outside ofthe furnace body, as shown inthe drawings. Thiscore may be supported, as shown, by brackets 45 hearthportion described is adaptedfor heating the bath i fpm spectivemagnesite portions ofthe body are Y dio secured to the sides ofthe lowerthe furnace.

At a suitable point around the core is provided the primary winding.This shown at 50 around the leg 42 ofthe core and thus entirely outsideof the furnace body, where' it will keep cool and be out of dangershould the molten metal break through the bottoln of the furnace, whichsometimes happens. This rwinding, more'- over, is shown as protectedfrom accident from'the outside by straps 52 carried by the frame work 20near. the ends of the winding.

The leg 41 of the core is properly ventilated by passing through anenlarged opening 35 in the body '30, and this-opening is covered by ametal protecting roof 36 secured to the body portion 10, and thetrough-shaped Iprotector 37 secured to the body portion 3..

The two portions of the furnace are clamped together when in use bysuitable clamps, some of which are illustrated in the drawings. Thus, inFigs. 1, 2 and 3, 60 indicates ear-brackets secured. to the body portion10, and -61 are bars pivoted to such brackets. These bars are adapted toextend between the earfbrackets 63 secured to the lower portion of thebody and be clamped thereto by Wedges or keys 64 driven through the earsand bars. This provides for drawing the two sections of the furnacetightly together. I

To prevent leakage of the molten materialout of the U-shaped passagewayat the junction of the upper and lower parts of the furnace, I provide aspecial construction illustrated in Figs. 2, 6 and 5, which is animportant feature of this invention. Such construction consists of rings71 of magnesite, or similar material, which surround the legs of thepassageway and occupy grooves in the meeting faces of the two portlonsof the furnacebody, being embedded in cement therein, and thus interruptand cut oif any passage existing between these faces. TheseA rings arepreferably round in course, and their cross section ,is preferablycircular. They occupy correspondingly placed grooves in the material of10 and 30, the grooves being somewhat larger than half of the ring, spthat there is room for-cement about the rm 'Ighe cement between thefurnace section is illustrated clearly at 73 in Fig. 5, and may `be ofmaterial similar to the furnace bodies. It extends about both sides ofIthe rings 71 and along the junction of the two body portions 10, and3,0. After being so placed, and before the cement has set, the wedges 64of the clampsY described are driven into place thus drawing the twoportions of the ,-gether and making a tight connection urnace bodytightly toaound the U legs.

portion of A two-part furnace construct-ed as described is readilyadapted for tilting to pour out the linished material. To that end theframework 20, heretofore refell'edto, may conveniently be pivoted at 21to the standards 22 supporting one side, while the other side may beconnected with connecting rods 24, whose pistons 25 occupy stationarycylinders 26. When fluid is admitted to these cylinders the pipes 27beneath the istons, the pistons are raised thereby to tilt the furnacestructure about the pivots 21, thus pouring the molten 'metal out oftheV tap 16.. At the end of the campaign, the material in the lll-shapedpassageways may be drained therefrom, if desired, by tilting the furnaceover farther. This may be done by connecting a4 suitable hoist with theeye 29.

When it is desired to separate the furnace for purposes of repairLorotherwise, it is simply necessary to drive out the keys 64 and attach asuitable hoistf` to the upper section of the furnace. For purposes ofsuch attachment, suitable hooks may be secured to the furnace body, as,for example, the hooks 75 shown in Fig. 2.

It will be noted that the leg of the passageway 33 which communicateswith the passageway 19 is larger in cross section than the other leg.The purpose of this unequal material to become hotterin one leg than inthe other, whereby the result-ing tendency to rise causes a continuouscirculation. of the material through the legs and a portion of the bath,thereby continuously agitating and circulating the material 'in' thebath. Similarly, in Fig. 6 the common leg 19a is preferably of dilferentcross sectional area than thesum of the areas across the individuallegs. i y

It will be seen that,l in practice, my furnace operates as if it were'one solid unitary structure, while, whenever separation of the parts, oraccess, to the induction coil,I is desired it may be very easilyobtained. Tov repair .the primary winding, for example, or the lowerportion of the furnace, it is only necessary to disconnect the clampsand set aside the upper part of the furnace. This provides access to thelower part and enables the core and primary) winding to be entirelyremoved and repaired most conveniently. As'the greatest wear comes onthe hearth portion of the furnace, it is feasible to have two or moresuch portions to go with one lower portion, and,.a's soon as theupper'portion ,is worn, to remove it and substitute a new portion, thusentailing no delay while the hearth portion is being repaired. By havingthe primary winding entirely outside of the furnace body it is not onlyperfectly ventilated and keeps cool, but it is protected from damage byany `cross, section of the two legs is to cause the municate with theopenings referred to,

means for clamping the two portions ofthe furnace together for use andreleasing the two portions for repairs. and replacement, and a core andprimary winding adapted to cause the material in the passageway and aportion of that in 'the' bath to become 'an annular secondary.

2. The combination of a separable two- A partV induction furnace'havinga conjoint passageway for molten metal, and means for making anon-fusible liquid-tight joint between the two parts of the furnace.v

3. The combination of a separable two part furnace having a basin and aU-shaped passageway communicatingtherewith, the bent portion oftheU-shaped passageway being in one member of the "furnace, and portions ofthe legs of the U` being in the other part-of the furnace,`and meanssurrounding a leg of the U and embedded in the adjoining faces of thetwo parts of the furnace.

4. In an electric furnace, the combination Aof an upper portion havingopenings through the bottom thereof, a lower portion having aU-shapedpassageway, the legs of which are adapted to communicate withthe openings referred to, and al ring embeddedl in the adjoining facesofthe upper and I' lower portions of the furnace and surrounding thejunction of one of said openings with a leg of the passageway.

5. In an electric furnace, the combination y of a hearth portion havinga basin and provided with openings through .its bottom communicatingwith the basin, a base portion having a U-shaped passageway, the legs ofwhich are adapted to communicate with the openings refered to, ringsembedded in the adjoining faces of the two ortions of the furnace aroundthe respective legs of the U, and clamps for drawing the two parts ofthe furnace snugly together.

6. The combination of a base portion having one or more verticalU-shaped passageways therein, a hearth portion adaptedv to surmount thebase portion and having openings through its bottom adapted tovcommunicate with the legs of said passageway, the openings communicatinat their upper ends with a basin in the hearth portion, and

rings at the junction of the two portions of the furnace surrounding theconduits provided by the passageways and openings described. 'p y 7. Thecombination of abase portion having one or more vertical U-shapedpassa-geways therein, ahearth portion'adapted to surmount the baseportion and having openings adapted to communicate with the legs of saidpassageway, the openings communieating at their upper ends with a basinin the hearth portion, and-rings surrounding `the conduits provided bythe openings and passageway, said rings being embedded in Cementoccupying grooves in the adjacent.

top and bottom faces ofthe base and hearth portionsI of the furnacerespectively.

8. In a furnace, the vcombination of a base portion having a U-shapedpassageway therein arranged in a substantially vertical plane, said baseportion consisting of heat resisting material and a suitable frame work,said material being exposed at its upper face, a top portion for thefurnace, having a heat resisting body carrying a basin with walls andaroof, openings throughthe'body `from the basin adapted to communicatewith the legs of the U in the'base portion, the underA portion of saidtop part ,being 'exposed about the legs so that such to-p por- .tion mayhave its heat resisting material come into coaction with "the heatresisting material of the base portion, cement between the two portions,and rings located at the junction of the two portions and embedded ingrooves therein and extending around'the legs of the U-shaped passagewayand said openings, combined with a core and primary of an induction coilcoacting with material in the basin and U-shaped passageway to makeofthe same an annular molten secondary.

9. In an electric furnace, the combination, with a basin, of a U-shapedpassageway for molten metal located in a vertical plane andcommunicating'with the bottom of the basin, an annular horizontal corelying beneath the basin and surrounding one of the legs of the U, and aprimary winding for said core located .entirely outside of the furnacebody. I 10. The combination, with the base portion of a furnace, meansarranged to tilt the same, of a surmounting portion, means to clamp iton the base portion, a U-shaped passageway in the base portion, andcommunicatingv openings through the bottom ofthe surmounting portionadapted to continue the legs of the U-shaped passageway intolcommunication with material in the basin, a closed magnetic coreextending around one or more of said legs, and a pri.- mary winding forsaid core.

1l. In an electric furnace, the combination' of a base portion,meansadapted to support and tilt the same,\ a"surmounting portion havinga basin, a U-shaped passageway lying partly in the base portiony andpartly in the surmounting portion, a ring embedded in the two portionsand surrounding the legs of such passageway, means for clamping the twoportions together, a core surrounding one or more of said legs, and oneor more primary windings `for said core..

12. In an electric furnace, the combination of a base portion,means'adapted to support y and tilt the same, a surmounting portionhaving a basin, a U-shaped passageway lying partly in the base portionand partly in the surmounting portion, a core'surrounding a leg of saidpassageway, a primary winding for said core, said core occupying anopening in the base portionnear the top thereof, which opening isexposedwhen the topportion-of the furnace is removed.

13. In an electric furnace, the combination of a base portion, aremovable top portion carrying a basin,'a U-shaped passageway containedpartly in the base portion and partly in the top portion, and a core andprimary winding of4 an induction coil, of which material in thepassageway and in the basin may constitute the secondary.

14. In an electric furnace, the combination -of a base portion, aremovable top portion carrying a basin, a U-shaped passageway containedpartly in the base portion and partly in the top portion, ringsindividually surrounding the legs of the U-shaped passageway at thejunction of the top and bottom thereon, ymeansfor clamping -it to thebase' portion, said top portion having a basin with a roof, loadingopenings and a'. pouring spout, lthere being a U-shaped passagewaycommunicating with the basin and contained partly inthe top portion andpartlyv in the baseportion, individual. rings surroundmg the '--Iegsbf'such passageway andJembedde 1,oee,924

in the two portions where they join, a closed magnetic core lying in ahorizontal plane and occupying a recess in the base portion covered bythe top portion but exposed when the top portion is removed, and awinding for Isaid core outside of the base portion.

16. The combination of a separable twopart induction furnace having apassageway for molten metal, means for making a liquid nace around saidpassageway, a core extending around the passageway and occupying arecess in the furnace body which, when the two portions are separated,is uncovered sufficiently to allow the removal of the core intact.

17. The combination in a separable tWO- part inductionA furnace of abase portion, a top portion removably mounted thereon, one or moreU-shaped passageways in the base portion and extending through thebottom of the top portion to a basinformed in the top portion, meansfor. forming a liquidti,`fg;hty

-joint around the legs 'of the U between the 'junction of the twoportions, a core surrounding the leg of the U and occupying a recessbetween the two portions of thefurnacel normally closed.- above-andbelow but uncovered when ,the top portion is removed,

tight joint between the -two parts of the fura primary winding-for suchcore, and clamps for holding the 'two lpartskf the furnace together inuse.

18. In an electric `furnace, the combination of two portions, onesurmountng the other, the upper portignhavinga basin, a Ushapedpassageway .for-molten" metal located vin a vertical plane in the twoportions and communicating -with the bottom ofthe basin, an

annular horizontal core lying beneath the ybasin and surrounding one ofthe legsof the U and having its inner leg in the recess in the furnacebody located at the junction of the portions and uncovered when the topportionsare moved, and a primary winding on said core located entirelyoutside'of the furnace'body. l v

In testimony whereof, I hereunto aiix my signature in the presence oftwowltnesses.

v WALTER N. CRAFTS.

Witnesses: 'I

